The singer said he is looking forward to performing with the group once more.

"We've got together, done bits and bobs," he revealed in a recording of Friday Night With Jonathan Ross. Asked if they would soon be reunited on stage, he replied: "I can't say much but, yes, I hope so."

Williams quit the band in 1995 and did not speak to band member Gary Barlow for more than a decade. They became friends again last year and were recently spotted entering the same recording studio in New York, fuelling rumours of a reunion.

Elsewhere in the interview, to be shown on BBC One this Friday, Williams, spoke of his plans to have children with girlfriend Ayda Field.

"I thought I was going to be a bachelor... I was introduced to Ayda and things just changed. She's a wonderful person and I'm in love. She's really broody and I'm getting there."

The singer's Electric Proms appearance last month was his first live gig in three years, and he told Ross that in the past the pressure of performing live had driven him to rehab.

"I've always been very nervous [performing for] 80,000 people, it's an unnatural thing to do," he said. "You don't know what's going on in my head. It's traumatic, really scary. I ended up in rehab again. It was, 'What are you doing to yourself?' I thought it was time to break the cycle.

"I've taken the pressure off myself, it's a part-time gig these days. The missus keeps me grounded. There's no need to take myself out of my mind any more."

Williams' wild-eyed comeback on The X Factor recently led some viewers to speculate that he was back on drugs. However, the singer insisted it was all down to nerves. "I get incredibly nervous. It wasn't drugs or drink, just deer in the headlights."